A three-dimensionally structured memory device is proposed in which a memory hole is formed in a stacked body where a plurality of electrode layers functioning as a control gate in a memory cell and insulating layers are alternately stacked, and in which a silicon body serving as a channel through a charge accumulation film is provided on a side wall of the memory hole.
In the three-dimensionally structured memory device described above, there is a concern that an electric field is concentrated in part (for example, a corner portion) of the electrode layer, and thus the endurance (repeated rewrite) characteristic is degraded.